CVE-2021-25916: Prototype pollution vulnerability in 'patchmerge' versions 1.0.0 through 1.0.1 allows an attacker to cause a d

Q: How do I fix CVE-2021-25916?

patchmerge: upgrade to newer than 1.0.1. Exact commands for each OS are on this page.

Q: Is CVE-2021-25916 being exploited?

CVE-2021-25916 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-25916 affect?

CVE-2021-25916 affects patchmerge. Severity is critical (CVSS 9.8). Prototype pollution vulnerability in 'patchmerge' versions 1.0.0 through 1.0.1 allows an attacker to cause a denial of service and may lead to remote code execution.

Q: How urgent is CVE-2021-25916?

Priority 67/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

CRITICAL 9.8REMOTEUPGRADE

CVE-2021-25916 is a critical-severity flaw (CVSS 9.8) affecting patchmerge. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Prototype pollution vulnerability in 'patchmerge' versions 1.0.0 through 1.0.1 allows an attacker to cause a denial of service and may lead to remote code execution.

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	3.5% (top 11%)
CISA exploited list	No
Weakness	CWE-1321
Published	2021-03-16
Last modified	2026-06-17

Publisher (CNA): Mend · Vendor: patchmerge project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-03-16 16:15 UTCPublished CVE record published
2026-06-17 03:42 UTCUpdated Record last modified

patchmerge project patchmerge UPGRADE

Affected: >= 1.0.0 and <= 1.0.1

Fixed in: newer than 1.0.1

Safe to downgrade to: a release before 1.0.0

1. Check installed version

npm ls patchmerge

2. UPGRADE to newer than 1.0.1

npm install patchmerge@">1.0.1"

3. If no update is available yet, DOWNGRADE to a release before 1.0.0

npm view patchmerge versions npm install patchmerge@"<1.0.0"

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-25916?

patchmerge: upgrade to newer than 1.0.1. Exact commands for each OS are on this page.

Is CVE-2021-25916 being exploited?

CVE-2021-25916 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-25916 affect?

CVE-2021-25916 affects patchmerge. Severity is critical (CVSS 9.8). Prototype pollution vulnerability in 'patchmerge' versions 1.0.0 through 1.0.1 allows an attacker to cause a denial of service and may lead to remote code execution.

How urgent is CVE-2021-25916?

Priority 67/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

References

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